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Viscosity Coefficient Curve Fits for Ionized Gas Species Grant PalmerViscosity coefficient curve fits for neutral gas species are available from many sources. Many do a good job of reproducing experimental and computational chemistry data. The curve fits are usually expressed as a function of temperature only. This is consistent with the governing equations used to derive an expression for the neutral species viscosity coefficient. Ionized species pose a more complicated problem. They are subject to electrostatic as well as intermolecular forces. The electrostatic forces are affected by a shielding phenomenon where electrons shield the electrostatic forces of positively charged ions beyond a certain distance. The viscosity coefficient for an ionized gas species is a function of both temperature and local electron number density. Currently available curve fits for ionized gas species, such as those presented by Gupta/Yos, are a function of temperature only. What they did was to assume an electron number density. The problem is that the electron number density they assumed was unrealistically high. The purpose of this paper is two-fold. First, the proper expression for determining the viscosity coefficient of an ionized species as a function of both temperature and electron number density will be presented. Then curve fit coefficients will be developed using the more realistic assumption of an equilibrium electron number density. The results will be compared against previous curve fits and against highly accurate computational chemistry data.
Document ID
20020042711
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Palmer, Grant
(NASA Ames Research Center Moffett Field, CA United States)
Arnold, James O.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Inorganic, Organic And Physical Chemistry
Meeting Information
Meeting: 8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference
Location: Saint Louis, MO
Country: United States
Start Date: October 19, 2001
Sponsors: American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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